Under basal conditions, the interaction of the cytosolic protein Keap1 (Kelch-like ECHassociated protein 1) with the transcription factor nuclear factor-E 2 -related factor 2 (Nrf2) results in a low level of expression of cytoprotective genes whose promoter region contains the antioxidant response element (ARE). Alkylation of one or more of the 27 cysteine sulfhydryl groups of human Keap1 is proposed to lead to Nrf2 nuclear accumulation, to upregulation of cytoprotective gene expression by the ARE, and to prevention of degenerative diseases, such as cancer. Therefore, identification of the most reactive of these cysteine residues toward specific electrophiles should help clarify this mechanism of cancer prevention, also known as chemoprevention. To address this issue, preliminary analyses of tryptic digests of Keap1 alkylated by the model electrophile 1-biotinamido-4-(4=-[maleimidoethyl-cyclohexane]-carboxamido) butane were carried out using liquid chromatographic-tandem mass spectrometry (LC-MS/MS) with a cylindrical ion trap mass spectrometer and also using LC-MS/MS with a hybrid linear ion trap FT ICR mass spectrometer. Because the FT ICR instrument provided more complete peptide sequencing coverage and enabled the identification of more alkylated cysteine residues, only this instrument was used in subsequent studies of Keap1 alkylation by three electrophilic natural products that can upregulate the ARE, xanthohumol, isoliquiritigenin, and 10-shogaol. Among the various cysteine residues of Keap1, C151 was most reactive toward these three electrophiles. These in vitro results agree with evidence from in vivo experiments, and indicate that C151 is the most important site of alkylation on Keap1 by chemoprevention agents that function by activating the ARE through Nrf2. Keap1 has five distinct domains: the N-terminal domain (amino acids 1-60); the BTB (Bric-a-brac, Tramtrack, Broad-complex) domain (amino acids 61-178); a central linker domain (amino acids 179 -321); the Kelch repeat domain (amino acids 322-608); and a C-terminal domain (amino acids 609 -625). The BTB domain mediates the dimerization of Keap1 [9] and also binds the adaptor protein in Cul3-dependent ubiquitination systems [10]. The Kelch repeat domain binds to the Nrf2 directly [1]. Because Keap1 signaling is probably mediated by alkylation of one or more of its cysteine sulfhydryl groups [3,11,12], identification of the cysteine residues that are most reactive toward specific electrophiles should help clarify this mechanism of action of Keap1.However, most of the work to date to identify reactive Keap1 cysteine residues has been carried out with model alkylating agents such as dexamethasone 21-mesylate [2], iodoacetyl-N-biotinyl hexylene diamine (BIA), and 1-biotinamido-4-(4=-[maleimidoethylcyclohexane]-carboxamido) butane (BMCC) [13] instead of biologically relevant ARE inducers that show promise as chemopreventive agents. Unlike ARE inducAddress reprint request to Professor Richard B. van Breemen,

ObjectiveCurrent diagnostic assessment tools remain suboptimal in demonstrating complex morphology of congenital heart disease (CHD). This limitation has posed several challenges in preoperative planning, communication in medical practice, and medical education. This study aims to investigate the dimensional accuracy and the clinical value of 3D printed model of CHD in the above three areas.MethodsUsing cardiac computed tomography angiography (CCTA) data, a patient-specific 3D model of a 20-month-old boy with double outlet right ventricle was printed in Tango Plus material. Pearson correlation coefficient was used to evaluate correlation of the quantitative measurements taken at analogous anatomical locations between the CCTA images pre- and post-3D printing. Qualitative analysis was conducted by distributing surveys to six health professionals (two radiologists, two cardiologists and two cardiac surgeons) and three medical academics to assess the clinical value of the 3D printed model in these three areas.ResultsExcellent correlation (r = 0.99) was noted in the measurements between CCTA and 3D printed model, with a mean difference of 0.23 mm. Four out of six health professionals found the model to be useful in facilitating preoperative planning, while all of them thought that the model would be invaluable in enhancing patient-doctor communication. All three medical academics found the model to be helpful in teaching, and thought that the students will be able to learn the pathology quicker with better understanding.ConclusionThe complex cardiac anatomy can be accurately replicated in flexible material using 3D printing technology. 3D printed heart models could serve as an excellent tool in facilitating preoperative planning, communication in medical practice, and medical education, although further studies with inclusion of more clinical cases are needed.

The roots of Angelica sinensis (Oliv.), Diels (Dang Gui; Apiaceae) have a long history in traditional Chinese medicine as a remedy for women's disorders, and are often called "lady's ginseng". Currently, extracts of A. sinensis are commonly included in numerous dietary supplements used for women's health and as anti-aging products. In the present study, we examined the potential chemopreventive activity of A. sinensis extracts by measuring the relative ability to induce the detoxification enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1). The lipophilic partitions showed strong NQO1 induction with concentrations to double the enzyme activity (CD) of 5.5 ± 0.7 μg/mL (petroleum ether) and 3.9 ± 0.5 μg/mL (chloroform). Fractionation led to the isolation of phenolic esters and alkylphthalides, especially Z-ligustilide, the main lipophilic compound, which showed strong NQO1 inducing properties (CD = 6.9 ± 1.9 μM). Transcription of many detoxifying enzymes is regulated through the antioxidant response element (ARE) and its transcription factor Nrf2, which is repressed under basal conditions by Keap1. However, exposure to electrophilic inducers that alkylate Keap1 results in a higher concentrations of free Nrf2 and ARE activation. The ARE reporter activity was therefore analyzed in HepG2-ARE-C8 cells after incubation with lipophilic extracts of A. sinensis or ligustilide for 24 h. Under these conditions, both the extract and ligustilide increased AREluciferase reporter activity in a dose-dependent manner. Incubation of ligustilide with GSH and subsequent LC-MS-MS analysis revealed that ligustilide as well as oxidized ligustilide species covalently modified GSH. In addition, using MALDI-TOF mass spectrometry and LC-MS-MS, it was demonstrated that the lipophilic extracts, ligustilide, and monooxygenated ligustilide alkylated important cysteine residues in human Keap1 protein, thus activating Nrf2 and transcription of ARE regulated genes. These observations suggest that A. sinensis dietary supplements standardized to ligustilide have potential as chemopreventive agents through induction of detoxification enzymes.

Retinoid X receptors (RXRs) function as ligand-activated transcription factors and are obligatory components of a large number of nuclear receptor heterodimers. RXRs help regulate diverse physiological responses including the cancer prevention responses of cell proliferation, inflammation, cell differentiation, and apoptosis. Since RXRs represent important targets for cancer chemoprevention, an ultrafiltration mass spectrometry-based assay was developed to facilitate the discovery of potential chemoprevention agents that bind to human RXRα. Natural and synthetic ligands for RXRα including 9-cis-retinoic acid, docosahexaenoic acid and LG100268 could be detected and identified in DMSO or even complex matrices such as extracts of marine bacteria. Specific binding of ligands to RXRα was demonstrated through competitive binding using ultrafiltration LC-MS-MS, and ligands could be ranked in order of affinity for RXRα. Therefore, ultrafiltration LC-MS-MS is suitable for the screening of complex mixtures such as natural product extracts for the discovery of new ligands to RXRα.

ABSTRACT:Isoliquiritigenin (2,4,4-trihydroxychalcone), a chalcone found in licorice root and other plants, has shown potent antitumor, antioxidant, and phytoestrogenic activity in vitro. In preparation for in vivo studies, the metabolism of isoliquiritigenin by human liver microsomes was investigated, and seven phase 1 metabolites were identified. In addition to aromatic hydroxylation that occurred on the A or B ring to form 2,4,4,5-tetrahydroxychalcone or butein, respectively, reduction of the carbon-carbon double bond of an ␣,␤-unsaturated ketone and cyclization occurred to form 2,4,4-trihydroxydihydrochalcone and (Z/E)-6,4-dihydroxyaurone. All metabolites were characterized and identified by using liquid chromatography-tandem mass spectrometry with comparison to authenticated compounds. Finally, monoclonal antibody inhibitors of specific human cytochrome P450 (P450) enzymes and recombinant human P450 enzymes were used to identify the enzymes responsible for the formation of the major mono-oxygenated metabolites, and P450 2C19 was found to be a significant enzyme in the formation of butein from isoliquiritigenin, which also has anticancer activity. Cytochromes P450, reactive oxygen species, and peroxidases can all contribute to the formation of (Z/E)-6,4-dihydroxyaurone in human liver microsomes.

Cardiac magnetic resonance (CMR) offers superior advantages in cardiac imaging due to supplying a greater field of view, excellent soft-tissue imaging, and multiplanar imaging capabilities. CMR imaging can evaluate the characteristics of cardiac tumors by visualizing the relationship between the tumor and surrounding tissues, and plays a vital role in assisting the formulation of the surgical plan, the assessment of tumor progression, and the monitoring of postoperative tumor recurrence and metastasis. In this review, we present the clinical manifestations and imaging features of different cardiac tumors. The superior performance of CMR in preoperative diagnosis, surgical treatment, and postoperative follow-up of patients with heart tumors are also highlighted.

The aim of this systematic review is to analyse current literature related to the clinical value of three-dimensional (3D) printed models in renal disease. A literature search of PubMed and Scopus databases was performed to identify studies reporting the clinical application and usefulness of 3D printed models in renal disease. Fifteen studies were found to meet the selection criteria and were included in the analysis. Eight of them provided quantitative assessments with five studies focusing on dimensional accuracy of 3D printed models in replicating renal anatomy and tumour, and on measuring tumour volume between 3D printed models and original source images and surgical specimens, with mean difference less than 10%. The other three studies reported that the use of 3D printed models significantly enhanced medical students and specialists' ability to identify anatomical structures when compared to two-dimensional (2D) images alone; and significantly shortened intraoperative ultrasound duration compared to without use of 3D printed models. Seven studies provided qualitative assessments of the usefulness of 3D printed kidney models with findings showing that 3D printed models improved patient's understanding of renal anatomy and pathology; improved medical trainees' understanding of renal malignant tumours when compared to viewing medical images alone; and assisted surgical planning and simulation of renal surgical procedures with significant reductions of intraoperative complications. The cost and time associated with 3D printed kidney model production was reported in 10 studies, with costs ranging from USD$100 to USD$1,000, and duration of 3D printing production up to 31 h. The entire process of 3D printing could take up to a few days. This review shows that 3D printed kidney models are accurate in delineating renal anatomical structures and renal tumours with high accuracy. Patient-specific 3D printed models serve as a useful tool in preoperative planning and simulation of surgical procedures for treatment of renal tumours. Further studies with inclusion of more cases and with a focus on reducing the cost and 3D model production time deserve to be investigated.

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